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Z(4430) and related results at Belle

Z(4430) and related results at Belle. Outline Observation of Z + (4430)→ ψ ’ π + in B→ ψ ’ π + K decays Z(4430) interpretation within 4-quark model Recent results on X(3872) Summary. Jolanta Brodzicka (KEK) 20/11/2007 KEK. Recent KEK press release.

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Z(4430) and related results at Belle

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  1. Z(4430) and related results at Belle Outline • Observation of Z+(4430)→ψ’π+ in B→ψ’π+K decays • Z(4430) interpretation within 4-quark model • Recent results on X(3872) • Summary Jolanta Brodzicka (KEK) 20/11/2007 KEK

  2. Recent KEK press release Jolanta Brodzicka Z(4430) and related KEK 20/11/20072

  3. Tsukuba • Asymmetric e+e- collider • e+: 3.5 GeV  e-: 8.0 GeV • CM energy: 10.58 GeV at (4S) • e+e-  (4S)  BB • Advantages: • exclusive source of BB pairs • useful kinematical constraints • high signal-to-background ratio • separation of B decay vertices • Record luminosity peak:1.711034cm-2s-1 • Integrated luminosity: ~742 fb-1 • ~ 780 * 106 BB • Beauty Factory KEK B Factory Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 3

  4. Aerogel Cherenkov Counter Time of Flight Counter Central Drift Chamber SC Solenoid 1.5T KL /Detector Silicon Vertex Detector Electromagnetic Calorimeter • Event reconstruction Charged tracks • Central Drift Chamber • Silicon Vertex Detector Electrons and photons • Electromagnetic Calorimeter 3.5 GeV e+ Belle Detector • Particle identification • K/ separation • Central Drift Chamber: dE/dx • Aerogel Cherenkov Counter • Time of Flight Counter • Electron identification • Electromagnetic Calorimeter KL and  identification • KL and muon detector Vertexing • Silicon Vertex Detector 8 GeV e- Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 4

  5. Cabbibo-favored vertices b c u, dc s K(*) u, d B charmonium (-like) W Good place for spectroscopy study! Charmonium(-like) factory Following B decays used: Advantages: b→cW→ccs is Cabbibo-favored process (not rare) background reduction is possible JPof parent B is known → JPof the child particles can be determined from angular analysis Jolanta Brodzicka Z(4430) and related KEK 20/11/20075

  6. Study of B→ψ’π+K B0 →ψ’π+K- and B+→ψ’π+K0s studied using 657·106 BB data ψ’→ e+e-, μ+μ- or J/ψπ+π- J/ψ →e+e-, μ+μ- K0s→π+π- secondary particles combined to B→ψ’π+K candidates B signal identification takes advantage of Υ(4S)→BB kinematics: EB=Ebeam=√s/2in cms kinematical variables used in B factories Mbc= √E2beam- p2B beam-constrained mass (signal at mB~5.28GeV) ΔE=EB- Ebeam cms energy difference (signal peaks at 0) clear B signal seen hep-ex/0708.1790 Submitted to PRL Jolanta Brodzicka Z(4430) and related KEK 20/11/20076

  7. ??? M2(ψ’π+) K2*(1430) K*(890) M2(Kπ+) B→ψ’π+KDalitz plot Z+(4430) in addition to expected B→ψ’K* components a clear band seen at M2(ψ’π+)~20GeV2 to study ψ’π+ structure we apply K*veto (both K* regions excluded) M(ψ’π+) fitted with Breit-Wigner + phase-space like function prominent peak (K* veto applied) 3-body decays non-B background M(ψ’π+) Nsig =121 ± 30 (6.5σ) M= 4433 ± 4 MeV Γ= 45+18-13 MeV Jolanta Brodzicka Z(4430) and related KEK 20/11/20077

  8. Is Z(4430) signal robust? data subsets checked, K* veto changed → consistent Z parameters interference between different (S,P,D) Kπ partial waves → cannot produce such narrow peak in ψ’π+ B generic MC studied → Z(4430) is not a reflection interference with 3-body → does not affect Z parameters much anything else contributed besides vetoed K*’s? no conclusion: Z(4430) signal is robust M(Kπ) for Z(4430) signal region without K* veto Jolanta Brodzicka Z(4430) and related KEK 20/11/20078

  9. hep-ex/0708.1790 Submitted to PRL Z+(4430) Z+(4430) properties M(ψ’π+) we cannot determine its JP with present statistics First candidate for a charged charmonium-like state! Must be exotic! It could be a tetraquark state either diquark [cu][cd] or molecular (cd)(cu) (Charged states naturally appear within multiquark models) Jolanta Brodzicka Z(4430) and related KEK 20/11/20079

  10. u c d c Xu= Xd= u c d c Maiani, Polosa et al. PRD 71, 014028 (2005) hep-ph/0707.3354 hep-hp/0708.3997 Within 4-quark model(by Maiani, Polosa et al.) Z+(4430)→Ψ’π+ can be diquark-antidiquark state [cu][cd] charged member of JPC=1+- multiplet it can be radial excitation of lowest lying 4-quarks with JPC=1++: X0u[cu][cu] X0d[cd][cd] X(3872) is candidate for such 4-quark state (but doublet needed) Mass splitting: M(Xu ) - M(Xd) ~2(md – mu)=8 ± 3 MeV (but mixing possible) Production rates in charged B larger than in neutral B B+→K+Xu B0→K0Xd Jolanta Brodzicka Z(4430) and related KEK 20/11/200710

  11. PRL 91, 262001 (2003) Reminder on X(3872) M(J/Ψππ) X(3872)→J/Ψπ+π- observed B+→X(3872)K+ by Belle confirmed by BaBar, CDF, D0 PDG06: M=3871.2 ± 0.5MeV Γ<2.3MeV other decay modes: X(3872)→J/Ψγ, J/Ψω, DDπ favored spin-parity: 1++(by the decay modes and angular analysis by CDF/Belle) What is X(3872)? does not match any cc state predicted by quark models DD* molecule? MX-(MD*0+ MD0)= -0.6±0.6 MeV 4-quark? Would explain small width. Charged X should exist X(3872) properties still under investigation (mass, width, line shape, decay modes…) Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 11

  12. BELLE-CONF-0711 New X(3872)→J/ψπ+π-results B0→XK0s Ns=30±7 (6.5σ) B+→XK+ Ns=125±14 (12σ) First observation! Motivated by 4-quark model predictions B+→X(3872)K+ and B0→X(3872)K0s X(3872)→J/ψπ+π-with 657MBB control sample: B→ψ’K ψ’→J/ψπ+ π-(to calibrate mass & resolution) look at ΔM= M(J/ψπ+ π-) - M(J/ψ)+mJ/ψ models predicting different properties for X(3872) from neutral and charged B decays are disfavored Jolanta Brodzicka Z(4430) and related KEK 20/11/200712

  13. PRL 97, 162002(2006) hep-ex/0708.1565 Surprises from X(3872)→D*D X(3872) is very close to D*0D0 mass threshold BaBar: B+→D*0D0K K=K+or K0 D*0 →D0π0,D0γ (with 383·106 BB) Belle: B+→ D0D0 π0K K=K+or K0 (with 447·106 BB) mass ~4σ away from X →J/Ψπ+π- are there two states X(3872) and X(3875)? Ns=33 ± 7 (4.9σ) M(X)=3875.1+0.7-0.5 ±0.5 MeV Γ=3.0+1.9-1.4 ± 0.9 MeV Ns=24 ± 6 (6.4σ) M(X)=3875.4 ± 0.7+0.4-1.7 ±0.9 MeV Γ=3.0+1.9-1.4 ± 0.9 MeV Jolanta Brodzicka Z(4430) and related KEK 20/11/200713

  14. Still within 4-quark model?(by Maiani, Polosa et al.) u c d c Xu= Xd= u c d c Maiani, Polosa et al. hep-ph/0707.3354 hep-hp/0708.3997 Model revised: Xustate decaying to D0D0π0 / D*0D0= X(3875) Xdstate decaying to J/Ψπ+π-= X(3872) (why Xd lighter than Xu?) predictions on rates in B decays: neutral Z partner should exist M~ M(Z+(4430))+few MeV decay modes: Ψ’π0,Ψ’η or ηc(2S)ρ0, ηc(2S)ω charged partner for X(3872)/X(3875) M~3880MeV, decay modes: J/Ψπ+ or ηc(1S)ρ+ Jolanta Brodzicka Z(4430) and related KEK 20/11/200714

  15. Summary Z+(4430)→ψ’π+ observed in B→ψ’π+K by Belle First candidate for charged charmonium-like state. It is exotic! Tetraquark interpretation favored X(3872) →J/ψπ+π- ,DD* in B decays studied Recent results disfavor models that predict different properties between B+→XK+ and B0→XK0 Jolanta Brodzicka Z(4430) and related KEK 20/11/200715

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